2016 Midwest Bridge Preservation Partnership

Transcription

1 Thin Epoxy Overlay Treatments on Bridge Decks Michigan DOT Best Practices 2016 Midwest Bridge Preservation Partnership

2 MDOT Organization

3 Outline Jason DeRuyver, P.E. (517) History of Thin Overlays in Michigan Scoping the Thin Overlay Specifications Step by Step Ensuring Results Questions and Answers

4 Just another Tool in our tool box!

5 We ve Come A Long Way

6 We ve Come A Long Way

7 We ve Come A Long Way

8 We ve Come A Long Way

9 Since 2006 MDOT State Forces have placed 1.7 million square feet Michigan Bridge Contractors have placed 3.2 million square feet. Innovation has led to cost effective materials and application procedures

10 Scoping the Thin Overlay Any deck 1 year or older Any deck with a deck bottom rating of fair or better Any deck with a surface condition that would warrant deck patching rather than a rigid overlay. Any deck you want a higher Skid Number Typical Skid Number on Michigan Bridge Tined Bridge Deck is 40 Typical Skid Number on Michigan Bridge Deck with Thin Overlay is 65

11 Building a Successful Specification ACI Specification for Producing a skid resistant surface on Concrete by the use of Epoxy and Aggregate Aggregate Gradation Aggregate Hardness Surface Preparation Pull Off Test Moisture Test

12 Building a Successful Specification ACI Michigan Deviation from Specification Aggregate Hardness (Mohs = 6) But Michigan Plow blades have an equivalent Mohs Hardness of 7

13 Building a Successful Specification ACI Michigan Deviation cont. Surface Preparation (Free of loose an unsound material) ICRI states a CSP of 5 or greater for thin overlays Michigan Experience uses a CSP of 7 or greater Pull Off Test 250 psi test areas usually end up being the cleanest spot on the deck Requiring A CSP 7 everywhere avoids this.

14 Building a Successful Specification Removal Method

15 Building a Successful Specification Removal Method Microcracking

16 Building a Successful Specification ACI Key Note Moisture Test Evaluate moisture content for concrete by determining if moisture will collect at bond lines between concrete and epoxy coating before epoxy has cured.

17 Building a Successful Specification ACI Key Note Moisture Test Cannot be done with a moisture meter Cannot be done by stating an exact duration in the specification. Must be based on the selected product and the manufacturers expected cure time given atmospheric conditions at the time of installation. Don t let the contractor run the epoxy into a 5 gallon bucket to check set time. Use manufacturer tables.

18 Thin Overlay Surface Prep Surface preparation is everything for the long term performance of the Epoxy Polymer Overlay. All soft, weak surface mortar, laitance or carbonation must be removed to allow the epoxy compound to bond to the aggregate within the concrete matrix.

19 Thin Overlay Surface Prep Deck tining must be removed Michigan deck tining is wet installed. Wet installation pushes the aggregate down. Aggregate must be exposed Paint striping is a bond breaker If unsound areas are discovered delay application. Most manufacturers will not recommend their product be placed over concrete less than 28 days old. Vehicles are not allowed on the prepared surface

20 Thin Overlay Surface Prep

21 Tape Joints & Drains Well Epoxy is difficult to remove from strip seal gland

22 Blow off the Deck Dry, Oil Free Air for a final cleaning Brooms force dirt into the cracks

23 Final Cleaning Tip Check Underneath Contractor Vehicles

24 Installation Day Minimum recommended air and surface temperatures are 50 F and rising If precipitation is expected thin overlay should be delayed If shotblast deck gets rained on, the deck will need to be re-blasted and moisture tests redone.

25 Applying Epoxy Squeegee epoxy as soon as it is applied to the deck Thin epoxy overlay material estimate First course rate a minimum of 2.5 gal / 100sft Second course a minimum of 5 gal / 100sft

26 Applying Epoxy

27 Squeegeeing Epoxy Use spike shoes while squeegeeing Use notched squeegees that will spread the material at the Manufacturer s recommended thickness. Puddle the epoxy one inch up the barrier

28 Squeegeeing Epoxy

29 Squeegeeing Epoxy

30 Aggregate Placement Use of a pressurized pot quickly delivers even aggregate placement No visible wet spots Aggregate spread at 3.33 lbs/sft. for thin overlay epoxy

31 Aggregate Placement Use of a pressurized pot quickly delivers even aggregate placement No visible wet spots Aggregate spread at 3.33 lbs/sft. for thin overlay epoxy

32 Life Expectancy Thin Epoxy Overlays With proper surface preparation thin epoxy overlay treatments will last 15 to 20 years Old flood coats that crack may be crack chased with healer sealer epoxy Delaminated overlays may be repaired

33 Life Expectancy

34 Dark aggregate may be beneficial During the Winter Maintenance Season

35 Troubleshooting If the contractor is applying mechanically Always turn on / off nozzle over bucket

36 Troubleshooting If the contractor is hand mixing Watch for spills. Puddles of A or B on the deck will never set up right and / or form a bond breaker.

37 Identifying Future Problems Inadequate surface profile

38 Identifying Future Problems A&B Puddles

39 Ensuring a Quality Job When in doubt, add a 5 year warranty. MDOT 12SP-712C-01 Performance Warranty, Thin Epoxy Bridge Deck Overlay

40 Safety Consult SDS and follow state safety guidelines Respirator recommended Avoid skin contact, A and B by themselves are nasty. Use common sense Don t mix the material with other substances Don t Breathe in vapors from the Bucket while epoxy is Flashing

41 Thin Epoxy Overlay Summary Seals cracks in bridge deck by bridging Use on any deck 1 year old or greater with a fair or better top and deck bottom condition Increases skid resistance Dark Aggregates deter icing of the bridge deck Heavily dependent on surface preparation Life expectancy years Deck Preparation Rate 600 to 850 sft / hr Placement rate 1,000 3,500 sft / hr / layer

42 List of Helpful Documents SP for Thin Epoxy Polymer Bridge Deck Overlay SP for Performance Warranty, Thin Epoxy Bridge Deck Overlay SP for Removal of Thin Epoxy Polymer Bridge Deck Overlay Thin Epoxy Overlay Log Sheet Healer Sealer Log Sheet Results of Aggregate Wear Track Polishing Test MDOT Flood Coat Whitepaper

43 Jason DeRuyver, P.E. (517) Questions?